A benzophenone derivative photoinitiator, HBP-TDI-HQ-TDI-HBP (HTCTH), was synthesized based on 4-hydroxy benzophenone (HBP), toluene-2,4-diisocyanate (TDI) and hydroquinone (HQ). HTCTH was a more effective pho...A benzophenone derivative photoinitiator, HBP-TDI-HQ-TDI-HBP (HTCTH), was synthesized based on 4-hydroxy benzophenone (HBP), toluene-2,4-diisocyanate (TDI) and hydroquinone (HQ). HTCTH was a more effective photoinitiator which had longer wavelength absorption in the UV-vis absorption spectra than the low molecular counterpart benzophenone (BP). It showed that both rate of polymerization (Rp) and final conversion (P) increased with increase of amine and HTCTH concentration in photopolymerization.展开更多
A new polyvinylalcohol-based photopolymeric holographic recording material has been developed. The recording is obtained by the copolymerization of acrylamide and N-hydroxymethyl acrylamide. Diffraction efficiencies n...A new polyvinylalcohol-based photopolymeric holographic recording material has been developed. The recording is obtained by the copolymerization of acrylamide and N-hydroxymethyl acrylamide. Diffraction efficiencies near 50% are obtained with energetic exposure of 80mJ/cm^2. N-hydroxymethyl acrylamide can improve the optical quality of the film. With the increase of the concentration of N-hydroxymethyl acrylamide, the flatness of the film increases, scattering reduces and the straight image is clearer with a small distortion. The postexposure effect on the grating is also studied. The diffraction efficiency of grating increases further during postexposure, gradient of monomer exists after exposure.展开更多
The photosensitive initiating system composed of 7-diethylamino-3-(2'-benzimidazolyl)coumarin dye (DEDC) and diphenyliodonium hexafluorophosphate (DIHP) which act as the sensitizer and the initiator respectively, ...The photosensitive initiating system composed of 7-diethylamino-3-(2'-benzimidazolyl)coumarin dye (DEDC) and diphenyliodonium hexafluorophosphate (DIHP) which act as the sensitizer and the initiator respectively, can be used to initiate the polymerization of methyl methacrylate (MMA). The results showed that when exposed to visible light, coumarin dye/iodonium salt undergoes quick electron transfer from DEDC to DIHP and free radicals are produced. The visible light photoinduced reaction between DEDC and DIHP is mainly through the excited singlet state of DEDC and thus it is a little sensitive to O-2. The influence of concentration of DEDC, DIHP and MMA on the rate of photopolymerization of MMA was also investigated.展开更多
Photopolymerization of propargyl acetate (PAT) with Michler's ketone (MK) asphotoinitiator in benzene has been investigated for the first time. Some features of the PATphotopolymerization with MK as photoinitiator...Photopolymerization of propargyl acetate (PAT) with Michler's ketone (MK) asphotoinitiator in benzene has been investigated for the first time. Some features of the PATphotopolymerization with MK as photoinitiator is described.展开更多
In this paper, we experimentally investigate the dark diffusional enhancement of the optimized multiplexed grating in the phenanthrenequinone doped poly (methyl methacrylate) (PQ-PMMA) photopolymer. The possibilit...In this paper, we experimentally investigate the dark diffusional enhancement of the optimized multiplexed grating in the phenanthrenequinone doped poly (methyl methacrylate) (PQ-PMMA) photopolymer. The possibility of improving the holographic characteristics of the material through the dark enhancement is demonstrated. The optimal preillumination exposure and the optimal time interval between exposures are extracted to obtain the optimized diffraction efficiency, and their values are 3.4×103 mJ/cm2 and 2 min, respectively. The dark enhancement of the multiplexed grating is presented as an effective method to improve the response region and the dynamic range and to prevent saturation of the material. The dependence of the phenanthrenequinone concentration on the increment of the refractive index modulation is quantitatively studied, which provides a significant basis for improving the homogeneity in the multiplexed gratings using a quantitative strategy. Finally, a simple experimental procedure using the dark enhancement is introduced to improve the homogeneity of the diffraction efficiency and to avoid the complex schedule exposure.展开更多
We present holographic storage of three-dimensional(3D) images and data in a photopolymer film without any applied electric field.Its absorption and diffraction efficiency are measured,and reflective analog hologram...We present holographic storage of three-dimensional(3D) images and data in a photopolymer film without any applied electric field.Its absorption and diffraction efficiency are measured,and reflective analog hologram of real object and image of digital information are recorded in the films.The photopolymer is compared with polymer dispersed liquid crystals as holographic materials.Besides holographic diffraction efficiency of the former is little lower than that of the latter,this work demonstrates that the photopolymer is more suitable for analog hologram and big data permanent storage because of its high definition and no need of high voltage electric field.Therefore,our study proposes a potential holographic storage material to apply in large size static 3D holographic displays,including analog hologram displays,digital hologram prints,and holographic disks.展开更多
The photosensitive system which can initiate methyl methacrylate with visible light was composed of compound 1 bis( eta-5-cyclopentadienyl)-bis[2,6-difluoro-3-(1-H-pyrrolyl)phenyl]titanium (titanocene) and compound 2 ...The photosensitive system which can initiate methyl methacrylate with visible light was composed of compound 1 bis( eta-5-cyclopentadienyl)-bis[2,6-difluoro-3-(1-H-pyrrolyl)phenyl]titanium (titanocene) and compound 2 [(3,3'-carbonylbis(7-diethylamino coumarin)] (ketocoumarin dye). The high photosensitive initiating efficiency of this photosensitive system could be very promising for efficient system for laser (Ar+ 488 nm) to plate and photocuring for thick coating and ink. The variation of UV-visible spectrum of compound 2 during irradiation indicates that photolysis of compound 2 is through its triplet state and it can be quenched by O-2 The much quicker photobleaching of the photosensitive system suggests that there exists certain quick electron transfer reaction between compounds 1 and 2.展开更多
o-Chloro-hexaarylbiimidazole (o-Cl-HABI) can be sensitized efficiently by the dyes 1-ethyl-3'-methyl thiacyanine bromide (C1), 3,3'-diethyl thiacarbocyanine iodide (C2), and cyclopentanone 2,5-bis[2-(1,3 -dihy...o-Chloro-hexaarylbiimidazole (o-Cl-HABI) can be sensitized efficiently by the dyes 1-ethyl-3'-methyl thiacyanine bromide (C1), 3,3'-diethyl thiacarbocyanine iodide (C2), and cyclopentanone 2,5-bis[2-(1,3 -dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)ethylidene] (C3) through electron transfer proceses. When exposed to a xenon lamp (filtered by Pyrex glass), the photosensitive systems composed of o-Cl-HABI and the above dyes can produce free radicals which initiate the polymerization of MMA. The photopolymerization kinetics equation was obtained for the o-Cl-HABI/C2 system, R-p = K [C2](0.75)[o-Cl-HABI](0.44)[MTA](0.12)[MMA](1.0). A comparison of the influence of different dyes on the conversion of MMA photopolymerization was conducted.展开更多
Photopolymerization process of glycerin triglycidyl ether based systems was studied by an FT-IR spectrometer.An increase in the rate of polymerization for glycerin triglycidyl ether was evident when 3,4-epoxycyclohexy...Photopolymerization process of glycerin triglycidyl ether based systems was studied by an FT-IR spectrometer.An increase in the rate of polymerization for glycerin triglycidyl ether was evident when 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate was added to it.Its copolymerization mechanism was confirmed by using DSC analysis.The effect of ethoxylated trimethyol propane triacrylate on the rate of polymerization for glycerin triglycidyl ether was also studied,and the formation of interpenetrating network tightly cross-link was proposed.展开更多
Toluidine blue(TB) is a good sensitizer for the polymerization of acrylnmide(AM) induced by He-Ne laser. With TB as a sensitizer and various alcoholamine as donors, the photoredox of TB and the polymerization kinetics...Toluidine blue(TB) is a good sensitizer for the polymerization of acrylnmide(AM) induced by He-Ne laser. With TB as a sensitizer and various alcoholamine as donors, the photoredox of TB and the polymerization kinetics of AM induced by He-Ne laser were investigated. It was found that either for the photoredox of TB or for the polymerization of AM, the activity of alcoholamine increases in the order of EOA<DEOA <TEOA in TB-alcoholamine sensitized system. The overall apparent kinetic equations of AM polymerization at 30℃ have been determined. In addition, the molecular weights under various conditions was measured.展开更多
Controlled radical photopolymerization of n-butyl methacrylate(n-BMA) mediated by 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy(HTEMPO) was carried out in bulk at ambient temperature. It was found that obtained n...Controlled radical photopolymerization of n-butyl methacrylate(n-BMA) mediated by 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy(HTEMPO) was carried out in bulk at ambient temperature. It was found that obtained n-BMA homopolymers exhibited narrow polydispersities of around 1.4, which was characterized by GPC. Plots of number-average molecular weight vs. conversion and Ln([Mo]/[M]) vs. time were liner respectively, indicating that was a controlled photopolymerization.展开更多
Two iron-arene complex photoinitiators with different substituents in arene ligands were synthesized, their activities in initiating photopolymerization of cyclohexene oxide (CHO) were compared with that of IRGACURE 2...Two iron-arene complex photoinitiators with different substituents in arene ligands were synthesized, their activities in initiating photopolymerization of cyclohexene oxide (CHO) were compared with that of IRGACURE 261, a commercialized photoinitiator from Ciba-Geigy. A higher activity was found when the arene ligand was substituted with a stronger electron donating group. For the system initiated by IRGACURE 261 the concentration of active centers in CHO polymerization was determined and it was found that the concentration is maximum at around 35℃. The post (dark) polymerization was significant, the polymerization yield decreased with the increase of irradiation temperature and increased with the increase of post polymerization temperature. The results are interpreted based on the mechanism proposed by Lohse, et al..展开更多
In this work, a dual-side parabolic structural(DSPS) multimode interference(MMI) thermo–optic(TO) waveguide switch is designed and fabricated by using novel low-loss fluorinated photopolymer materials. Comparing with...In this work, a dual-side parabolic structural(DSPS) multimode interference(MMI) thermo–optic(TO) waveguide switch is designed and fabricated by using novel low-loss fluorinated photopolymer materials. Comparing with the traditional dual-side linear structural(DSLS) MMI device, the effective length of the MMI coupling region proposed can be effectively reduced by 40%. The thermal stability of the waveguide material is analyzed, and the optical characteristics of the switching chip are simulated. The actual performances of the entire MMI switch are measured with an insertion loss of7 dB, switching power of 15 m W and an extinction ratio of 28 dB. In contrast to the traditional MMI optical switch, the new type of parabolic structural MMI TO waveguide switch exhibits lower power consumption and larger extinction ratio. The compact fluorinated polymer MMI TO switches are suitable well for realizing miniaturization, high-properties, and lower cost of photonic integrated circuits.展开更多
The kinetics of the photopolymerization of sensitized acrylamide (AM) system induced by He-Ne laser has been investigated. Using methylene blue (MB)-triethanolamine (TEOA) as the photosensitive system, the photopolyme...The kinetics of the photopolymerization of sensitized acrylamide (AM) system induced by He-Ne laser has been investigated. Using methylene blue (MB)-triethanolamine (TEOA) as the photosensitive system, the photopolymerization followed a nonsteady-state kinetic scheme in the initial period of polymerization (the monomer conversion C%<2%) and then followed a steady-state kinetic scheme (5% >C%>2%). Accirding to the steady-state hypothesis, the mechanism of photopolymerization was proposed. The deduced kinetic equation of the photopolymerization of AM is in good coincidence with the experimental results.展开更多
The diphenyliodonium salt (DPIOC)/triethylamine (TEA) is used as photoinitiator for radical photopolymerization. It was found that a ground state CT complex formed between DPIOC as electron acceptor and TEA as electro...The diphenyliodonium salt (DPIOC)/triethylamine (TEA) is used as photoinitiator for radical photopolymerization. It was found that a ground state CT complex formed between DPIOC as electron acceptor and TEA as electron donor, which results in extending the photosensitivity range of DPIOC/TEA system up to above 500nm compared with DPIOC alone. The kinetic studies on photopolymerization of methyl methacrylate (MMA) were carried out in CH_3CN: H_2O (14: 1, v/v) mixture solution at 30℃ by dilatometer. The results obtained show that the polymerization rate (R_p) increases with increasing concentrations of DPIOC and TEA with exponent 0. 65 and 0. 62 respectively. The activation energy E_a and k_p/k_^(1/2) value were determined to be 4.1 Kcal mol^(-1) and 0.045 respectively. The other influence factors and reaction mechanism were also discussed.展开更多
Several dimethylamino-substituted chalcone (i .e. dimethylaminobenzal acetophenone) (DBA) derivatives with intramolecular charge transfer transition character were used as visible light sensitizers for radical photopo...Several dimethylamino-substituted chalcone (i .e. dimethylaminobenzal acetophenone) (DBA) derivatives with intramolecular charge transfer transition character were used as visible light sensitizers for radical photopolymerization initiated by iodonium salt (DPIO). Initiating radical species is produced from DBA sensitized photolysis of DPIO through the single electron transfer, accompanying the bleaching of DBA, The activity of DBA decreases as a function of substituent attached to phenyl ring in the order: DBA-2 (OCH_3) >DBA-1(H)> DBA-3 (Cl). The kinetic study on photopolymerization of MMA was carried out in CH_3CN solution at 30 ℃ by dilatometry. The polymerization rate was determined to be proportional to the concentration with exponents of 0.42, 0.25 and 0.86 for DPIO, DBA-1 and MMA, respectively.展开更多
Low molecular weight poly(glycidyl methacrylate)s (PGMAs) were prepared by photopolymerization in ethyl acetate, with benzophenone (BP) as photoinitiator, and triethylamine (TEA) as hydrogen donor. The existen...Low molecular weight poly(glycidyl methacrylate)s (PGMAs) were prepared by photopolymerization in ethyl acetate, with benzophenone (BP) as photoinitiator, and triethylamine (TEA) as hydrogen donor. The existence of semipinacol dormant end groups in PGMA was confirmed by FT-IR and ^1H-NMR, and the content of the semipinacol dormant groups was determined quantitatively by ^1H-NMR measurement. The effects of various thctors, such as reaction time, BP concentration and monomer concentration on the synthesis of the polymers were investigated systematically. The molecular weights of the polymers were also investigated with GPC. It is shown that increasing BP concentration and decreasing irradiation time and monomer concentration led to a significant decrease of the molecular weights.展开更多
The radiative curable dendritic acrylated aromatic/aliphatic polyesters based on pentaerythritol, 1,2,4 benzenetricaboxylic anhydride and epoxy propane modified with acryloyl chloride were synthesized via a diver...The radiative curable dendritic acrylated aromatic/aliphatic polyesters based on pentaerythritol, 1,2,4 benzenetricaboxylic anhydride and epoxy propane modified with acryloyl chloride were synthesized via a divergent procedure, and their photopolymerization kinetics was studied by photo differential scanning calorimetry. The mechanical properties and the morphology of the fracture surface of the cured dendritic polyester films were investigated by means of dynamic mechanical thermal analysis and scanning electron microscopy, respectively.展开更多
基金the National Natural Science Foundation of China(No.50473024)for its financial support.
文摘A benzophenone derivative photoinitiator, HBP-TDI-HQ-TDI-HBP (HTCTH), was synthesized based on 4-hydroxy benzophenone (HBP), toluene-2,4-diisocyanate (TDI) and hydroquinone (HQ). HTCTH was a more effective photoinitiator which had longer wavelength absorption in the UV-vis absorption spectra than the low molecular counterpart benzophenone (BP). It showed that both rate of polymerization (Rp) and final conversion (P) increased with increase of amine and HTCTH concentration in photopolymerization.
文摘A new polyvinylalcohol-based photopolymeric holographic recording material has been developed. The recording is obtained by the copolymerization of acrylamide and N-hydroxymethyl acrylamide. Diffraction efficiencies near 50% are obtained with energetic exposure of 80mJ/cm^2. N-hydroxymethyl acrylamide can improve the optical quality of the film. With the increase of the concentration of N-hydroxymethyl acrylamide, the flatness of the film increases, scattering reduces and the straight image is clearer with a small distortion. The postexposure effect on the grating is also studied. The diffraction efficiency of grating increases further during postexposure, gradient of monomer exists after exposure.
基金This work was supported by the National Natural Science Foundation of China (No. 59773011).
文摘The photosensitive initiating system composed of 7-diethylamino-3-(2'-benzimidazolyl)coumarin dye (DEDC) and diphenyliodonium hexafluorophosphate (DIHP) which act as the sensitizer and the initiator respectively, can be used to initiate the polymerization of methyl methacrylate (MMA). The results showed that when exposed to visible light, coumarin dye/iodonium salt undergoes quick electron transfer from DEDC to DIHP and free radicals are produced. The visible light photoinduced reaction between DEDC and DIHP is mainly through the excited singlet state of DEDC and thus it is a little sensitive to O-2. The influence of concentration of DEDC, DIHP and MMA on the rate of photopolymerization of MMA was also investigated.
文摘Photopolymerization of propargyl acetate (PAT) with Michler's ketone (MK) asphotoinitiator in benzene has been investigated for the first time. Some features of the PATphotopolymerization with MK as photoinitiator is described.
基金supported by the National Basic Research Program of China(Grant No.2007CB3070001)the Fundamental Research Funds for the Central Universities,China(Grant No.HIT.NSRIF.2010009)+1 种基金the Program of Excellent Team in Harbin Institute of Technology,Chinathe Research Startup Foundation of Civil Aviation University of China(Grant No.2010QN03X)
文摘In this paper, we experimentally investigate the dark diffusional enhancement of the optimized multiplexed grating in the phenanthrenequinone doped poly (methyl methacrylate) (PQ-PMMA) photopolymer. The possibility of improving the holographic characteristics of the material through the dark enhancement is demonstrated. The optimal preillumination exposure and the optimal time interval between exposures are extracted to obtain the optimized diffraction efficiency, and their values are 3.4×103 mJ/cm2 and 2 min, respectively. The dark enhancement of the multiplexed grating is presented as an effective method to improve the response region and the dynamic range and to prevent saturation of the material. The dependence of the phenanthrenequinone concentration on the increment of the refractive index modulation is quantitatively studied, which provides a significant basis for improving the homogeneity in the multiplexed gratings using a quantitative strategy. Finally, a simple experimental procedure using the dark enhancement is introduced to improve the homogeneity of the diffraction efficiency and to avoid the complex schedule exposure.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474194,11004037,and 61101176)the Natural Science Foundation of Shanghai,China(Grant No.14ZR1415500)
文摘We present holographic storage of three-dimensional(3D) images and data in a photopolymer film without any applied electric field.Its absorption and diffraction efficiency are measured,and reflective analog hologram of real object and image of digital information are recorded in the films.The photopolymer is compared with polymer dispersed liquid crystals as holographic materials.Besides holographic diffraction efficiency of the former is little lower than that of the latter,this work demonstrates that the photopolymer is more suitable for analog hologram and big data permanent storage because of its high definition and no need of high voltage electric field.Therefore,our study proposes a potential holographic storage material to apply in large size static 3D holographic displays,including analog hologram displays,digital hologram prints,and holographic disks.
基金This work was financially supported by the National Nature Science Foundation of China (Project number: 59773011).
文摘The photosensitive system which can initiate methyl methacrylate with visible light was composed of compound 1 bis( eta-5-cyclopentadienyl)-bis[2,6-difluoro-3-(1-H-pyrrolyl)phenyl]titanium (titanocene) and compound 2 [(3,3'-carbonylbis(7-diethylamino coumarin)] (ketocoumarin dye). The high photosensitive initiating efficiency of this photosensitive system could be very promising for efficient system for laser (Ar+ 488 nm) to plate and photocuring for thick coating and ink. The variation of UV-visible spectrum of compound 2 during irradiation indicates that photolysis of compound 2 is through its triplet state and it can be quenched by O-2 The much quicker photobleaching of the photosensitive system suggests that there exists certain quick electron transfer reaction between compounds 1 and 2.
基金This project financially supported by National Natural Science Foundation of China (Project number 59973023)
文摘o-Chloro-hexaarylbiimidazole (o-Cl-HABI) can be sensitized efficiently by the dyes 1-ethyl-3'-methyl thiacyanine bromide (C1), 3,3'-diethyl thiacarbocyanine iodide (C2), and cyclopentanone 2,5-bis[2-(1,3 -dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)ethylidene] (C3) through electron transfer proceses. When exposed to a xenon lamp (filtered by Pyrex glass), the photosensitive systems composed of o-Cl-HABI and the above dyes can produce free radicals which initiate the polymerization of MMA. The photopolymerization kinetics equation was obtained for the o-Cl-HABI/C2 system, R-p = K [C2](0.75)[o-Cl-HABI](0.44)[MTA](0.12)[MMA](1.0). A comparison of the influence of different dyes on the conversion of MMA photopolymerization was conducted.
基金Funded by the Innovatory Group Program of the Natural Science Foundation of Hubei Province (2004ABC001)the National "863" Hi-tech Foundation of China (2002AA6Z3083)
文摘Photopolymerization process of glycerin triglycidyl ether based systems was studied by an FT-IR spectrometer.An increase in the rate of polymerization for glycerin triglycidyl ether was evident when 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate was added to it.Its copolymerization mechanism was confirmed by using DSC analysis.The effect of ethoxylated trimethyol propane triacrylate on the rate of polymerization for glycerin triglycidyl ether was also studied,and the formation of interpenetrating network tightly cross-link was proposed.
基金Supported by the National Natural Science Foundation of China
文摘Toluidine blue(TB) is a good sensitizer for the polymerization of acrylnmide(AM) induced by He-Ne laser. With TB as a sensitizer and various alcoholamine as donors, the photoredox of TB and the polymerization kinetics of AM induced by He-Ne laser were investigated. It was found that either for the photoredox of TB or for the polymerization of AM, the activity of alcoholamine increases in the order of EOA<DEOA <TEOA in TB-alcoholamine sensitized system. The overall apparent kinetic equations of AM polymerization at 30℃ have been determined. In addition, the molecular weights under various conditions was measured.
基金Financially supports from the National Natural Science Foundation of China(No.20274023 and 20474036)Guangdong Province Natural Science Foundation(No.021241)are gratefully acknowledged.
文摘Controlled radical photopolymerization of n-butyl methacrylate(n-BMA) mediated by 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy(HTEMPO) was carried out in bulk at ambient temperature. It was found that obtained n-BMA homopolymers exhibited narrow polydispersities of around 1.4, which was characterized by GPC. Plots of number-average molecular weight vs. conversion and Ln([Mo]/[M]) vs. time were liner respectively, indicating that was a controlled photopolymerization.
基金Supported by the National Natural Science Foundation of China
文摘Two iron-arene complex photoinitiators with different substituents in arene ligands were synthesized, their activities in initiating photopolymerization of cyclohexene oxide (CHO) were compared with that of IRGACURE 261, a commercialized photoinitiator from Ciba-Geigy. A higher activity was found when the arene ligand was substituted with a stronger electron donating group. For the system initiated by IRGACURE 261 the concentration of active centers in CHO polymerization was determined and it was found that the concentration is maximum at around 35℃. The post (dark) polymerization was significant, the polymerization yield decreased with the increase of irradiation temperature and increased with the increase of post polymerization temperature. The results are interpreted based on the mechanism proposed by Lohse, et al..
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFB0402502)the National Natural Science Foundation of China(Grant Nos.61575076,61475061,61605057,and 61675087)the Jilin Provincial Industrial Innovation Special Fund Project,China(Grant No.2016C019)
文摘In this work, a dual-side parabolic structural(DSPS) multimode interference(MMI) thermo–optic(TO) waveguide switch is designed and fabricated by using novel low-loss fluorinated photopolymer materials. Comparing with the traditional dual-side linear structural(DSLS) MMI device, the effective length of the MMI coupling region proposed can be effectively reduced by 40%. The thermal stability of the waveguide material is analyzed, and the optical characteristics of the switching chip are simulated. The actual performances of the entire MMI switch are measured with an insertion loss of7 dB, switching power of 15 m W and an extinction ratio of 28 dB. In contrast to the traditional MMI optical switch, the new type of parabolic structural MMI TO waveguide switch exhibits lower power consumption and larger extinction ratio. The compact fluorinated polymer MMI TO switches are suitable well for realizing miniaturization, high-properties, and lower cost of photonic integrated circuits.
文摘The kinetics of the photopolymerization of sensitized acrylamide (AM) system induced by He-Ne laser has been investigated. Using methylene blue (MB)-triethanolamine (TEOA) as the photosensitive system, the photopolymerization followed a nonsteady-state kinetic scheme in the initial period of polymerization (the monomer conversion C%<2%) and then followed a steady-state kinetic scheme (5% >C%>2%). Accirding to the steady-state hypothesis, the mechanism of photopolymerization was proposed. The deduced kinetic equation of the photopolymerization of AM is in good coincidence with the experimental results.
文摘The diphenyliodonium salt (DPIOC)/triethylamine (TEA) is used as photoinitiator for radical photopolymerization. It was found that a ground state CT complex formed between DPIOC as electron acceptor and TEA as electron donor, which results in extending the photosensitivity range of DPIOC/TEA system up to above 500nm compared with DPIOC alone. The kinetic studies on photopolymerization of methyl methacrylate (MMA) were carried out in CH_3CN: H_2O (14: 1, v/v) mixture solution at 30℃ by dilatometer. The results obtained show that the polymerization rate (R_p) increases with increasing concentrations of DPIOC and TEA with exponent 0. 65 and 0. 62 respectively. The activation energy E_a and k_p/k_^(1/2) value were determined to be 4.1 Kcal mol^(-1) and 0.045 respectively. The other influence factors and reaction mechanism were also discussed.
文摘Several dimethylamino-substituted chalcone (i .e. dimethylaminobenzal acetophenone) (DBA) derivatives with intramolecular charge transfer transition character were used as visible light sensitizers for radical photopolymerization initiated by iodonium salt (DPIO). Initiating radical species is produced from DBA sensitized photolysis of DPIO through the single electron transfer, accompanying the bleaching of DBA, The activity of DBA decreases as a function of substituent attached to phenyl ring in the order: DBA-2 (OCH_3) >DBA-1(H)> DBA-3 (Cl). The kinetic study on photopolymerization of MMA was carried out in CH_3CN solution at 30 ℃ by dilatometry. The polymerization rate was determined to be proportional to the concentration with exponents of 0.42, 0.25 and 0.86 for DPIO, DBA-1 and MMA, respectively.
基金The authors are grateful to the National Natural Science Foundation of China (No. 50433040) for the financial support.
文摘Low molecular weight poly(glycidyl methacrylate)s (PGMAs) were prepared by photopolymerization in ethyl acetate, with benzophenone (BP) as photoinitiator, and triethylamine (TEA) as hydrogen donor. The existence of semipinacol dormant end groups in PGMA was confirmed by FT-IR and ^1H-NMR, and the content of the semipinacol dormant groups was determined quantitatively by ^1H-NMR measurement. The effects of various thctors, such as reaction time, BP concentration and monomer concentration on the synthesis of the polymers were investigated systematically. The molecular weights of the polymers were also investigated with GPC. It is shown that increasing BP concentration and decreasing irradiation time and monomer concentration led to a significant decrease of the molecular weights.
基金Supported by the National Natural Science Foundation of China(No. 2 0 0 74 0 34)
文摘The radiative curable dendritic acrylated aromatic/aliphatic polyesters based on pentaerythritol, 1,2,4 benzenetricaboxylic anhydride and epoxy propane modified with acryloyl chloride were synthesized via a divergent procedure, and their photopolymerization kinetics was studied by photo differential scanning calorimetry. The mechanical properties and the morphology of the fracture surface of the cured dendritic polyester films were investigated by means of dynamic mechanical thermal analysis and scanning electron microscopy, respectively.